Process for preparing a concentrate of a polyalpha-olefin in a lubricating oil base stock

Claim 1

The method for making a concentrate of a poly(1-alkene) in a lubricating oil base stock for use as an additive in preparing multiviscosity graded motor oils which comprises conditioning a hydrotreated mineral lubricating oil base stock having a 210° F. viscosity between about two cs. and about eight cs., by contacting it with a first Ziegler-Natta catalyst comprising a compound of a transition metal from Groups IV-B, V-B, VI-B or VIII at a valence state less than its maximum valence state and an organometallic compound of a Group II or III metal and hydrogen at a pressure between about one and about 150 psia. at a temperature between about -10° C. and about 125° C. for about 30 seconds to about one hour, using from about 0.01 to about 20 grams of said catalyst per liter of said hydrotreated lubricating oil base stock and a ratio of gram atoms of Group II or Group IIII metal to gram atoms of the transition metal of from about 1:1 to about 10:1, and contacting a 1-alkene reactant comprising about 70 to 100 mol percent of a 1-alkene having from six to 12 carbon atoms or a mixture thereof and 0 to about 30 mol percent of a 1-alkene having from 16 to 20 carbon atoms or a mixture thereof with a second Ziegler-Natta catalyst in the presence of about 10 to about 300 parts of the said conditioned hydrotreated lubricating oil base stock as a reaction medium per 100 parts of said 1-alkene reactant at polymerization conditions.

Claim 2

The method for making a concentrate of a poly(1-alkene) in a lubricating oil base stock for use as an additive in preparing multiviscosity graded motor oils which comprises conditioning a hydrotreated mineral lubricating oil base stock having a 210° F. viscosity between about two cs. and about eight cs., by contacting it with a first Ziegler-Natta catalyst comprising a compound of a transition metal from Groups IV-B, V-B, VI-B or VIII at a valence state less than its maximum valence state and an organometallic compound of a Group II or III metal and hydrogen at a pressure between about one and about 150 psia. at a temperature between about -10° C. and about 125° C. for about 30 seconds to about one hour, using from about 0.01 to about 20 grams of said catalyst per liter of said hydrotreated lubricating oil base stock and a ratio of gram atoms of Group II or Group IIII metal to gram atoms of the transition metal of from about 1:1 to about 10:1, and contacting a 1-alkene reactant comprising about 70 to 100 mol percent of a 1-alkene having from six to 12 carbon atoms or a mixture thereof and 0 to about 30 mol percent of a 1-alkene having from 16 to 20 carbon atoms or a mixture thereof with a second Ziegler-Natta catalyst in the presence of about 10 to about 300 parts of the said conditioned hydrotreated lubricating oil base stock as a reaction medium per 100 parts of said 1-alkene reactant at polymerization conditions.